This invention relates to shock-absorbing cushions. Commonly used shock-absorbing cushions are formed of air-cell cloth, foam plastic or rubber, etc., but they have the following defects in practical use.
1. The air-cell cloth is made of two sheets sealed together to pinch a plurality of independent air cells not communicating with one another, and each air cell is at atmospheric pressure which is unadjustable, having a constant shock-absorbing force so that it cannot be changed to cope with different objects.
2. The air cells contained in air-cell cloth are separately sealed to have the same inner pressure as the exterior atmospheric pressure, having no inherent supporting force for pressure or shock. Therefore, if the air cell(s) should be broken and become flat with the air having escaped, it (they) would have no supporting force for pressure or shock, and the cloth would become useless.
3. Every air cell in air-cell cloth is independent, and sealed to have a constant pre-set pressure, unable to be changed by inflation to have a wide adaptability.
4. Air-cell cloth has a flat shape, unable to be formed as a cubic shape having three dimensions.
5. The inner pressure of the air cells in air-cell cloth can not exceed 1 atm (kg/cm2) or 14.7 psi, restricted by its manufacturing method of xe2x80x9cvacuum absorbing formationxe2x80x9d so that air-cell cloth is impossible to make if the thickness or the hardness of the material surpasses a certain value, with the result that the supporting force of the air-cell cloth cannot be changed by the thickness, the hardness of the material, the shape or the size of the air cells.
6. Each air cell in air-cell cloth receives a different shock force when struck by an exterior object and the cloth is unable to disperse evenly the shock force received mainly because the cells do not communicate with one another.
7. A solid shock-absorbing cushion of foam plastic has a certain shock-absorbing force restricted by the property of the material so that it can hardly be used for different occasions, objects or things.
8. As the shape of a solid shock-absorbing cushion is impossible to change once made by a mold, it can hardly meet the necessity to protect the object it is used for by conforming completely to the shape and the size of the object.
9. U.S. Pat. No. 4,054,960 titled xe2x80x9cInflatable Body Support Cushion Particularly to Support a Woman During Pregnancyxe2x80x9d is a king of air-cushion bed for a pregnant woman made of a moldable material, but does not have the function of flexibility or inherent supporting force, as can be seen on page 1, lines 50-51 in the patent specification.
10. U.S. Pat. No. 4,629,433 titled xe2x80x9cInflatable Articles and Method of Making Samexe2x80x9d acquired by Magid, has a preventing function of deforming and extension of an inflatable article once inflated with air, but it is made of pieces so that the articles have no inherent supporting force, as can be seen on page 1, lines 64-65 and page 6, lines 67-68 in the patent specification.
11. U.S. Pat. No. 1,382,831 titled xe2x80x9cPneumatic Cushionxe2x80x9d is a sealed bag made of two sheets of material and said two sheets have thickened inner sides such that the bag can hold the outer surface flat after it is inflated with air. But it can hardly be flexible and lacks vertical supporting force against pressure.
12. U.S. Pat. No. 2,465,265 titled xe2x80x9cPneumatic Bedxe2x80x9d acquired by Rogers is a bag made of two sheets sealed at the circumferential edge and a third sheet is additionally put between and connected with the two sheets so that it can hold an extremely flat surface, but it has no flexibility or inherent supporting force against pressure or shock, as can be seen on pages 1-2, lines 49-52.
13. U.S. Pat. No. 2,372,218 titled xe2x80x9cPneumatic Mattressxe2x80x9d is provided with valves to inflate or deflate the mattress, but said pneumatic mattress has no inherent supporting force against pressure and the inflating valves have a different structure and function from the flexible pump to be disclosed herein.
14. U.S. Pat. No. 4,115,885 titled xe2x80x9cWater Cushion and Method of Using the Samexe2x80x9d acquired by Davis is a shock-absorbing bag filled with water, having no vertical supporting force against pressure.
15. U.S. Pat. No. 4,217,705 titled xe2x80x9cSelf-Contained Fluid Pressure Foot Support Devicexe2x80x9d is a bag sealed around the periphery of two sheets of non-elastic fabric and having a special section provided with round hollow cells defined by hot sealing, said round hollow cells being inserted by foot supporting cushions for supporting a foot. The cushion body is originally flat and has no inherent supporting force against pressure, as can be seen on page 7, lines 7-10. The so called supporting force is caused by the foot supporting cushions.
16. U.S. Pat. No. 2,677,906 titled xe2x80x9cCushioned Inner Sole for Shoes and Method of Making the Samexe2x80x9d acquired by Reed is a shoe sole made of two sheets having the periphery heat sealed and another sheet connected with the upper and the lower sheets so as to make up an inner shoe sole having a specially flat surface. But the air cushion has little flexibility and air cells independent to one another, whereby it is impossible to disperse the pressure received evenly around the structure and the inflating operation is complicated as well.
17. U.S. Pat. No. 3,991,420 titled xe2x80x9cProtective Baseball Batting Garmentxe2x80x9d acquired by Savarino is a protective jacket for baseball batting but the padded sections are not provided with air cushions.
18. U.S. Pat. No. 4,614,000 titled xe2x80x9cPatient Undersheet for Preventing Bed Soresxe2x80x9d acquired by Mager is a bed undersheet for a patient having a sheet of air-cell cloth with a sheet of fabric mounted thereon. The air-cell cloth has no structure or supporting force, nor does its air-cells communicate with one another, so it cannot be developed to make up a three-dimensional structure.
19. French Patent No. 540,623 is an air cushion made of two sheets of material sealed such that a plurality of independent air cells are formed therein, without any linking passages among the air cells. The air cushion has little flexibility and each air cell does not have even pressure.
20. Belgian Patent No. 645,151 is a shock-absorbing cushion made of two sheets of material with a water absorbing layer sandwiched between the two sheets, and the two sheets are provided with round recesses. It is made of two flat sheets, devoid of potential supporting force against pressure or shock, nor can it be inflated.
21. German Patent No. 807,010 titled xe2x80x9cSoft Layer Baby Diaperxe2x80x9d is provided with an inflated air cushion attached to an inflating pump. The cushion body is made of two sheets, devoid of inherent supporting force against pressure of flexibility caused by the absence of communicating passages.
22. French Patent No. 1,118,087 is made of two sheets sealed together with heat, and an extra two sheets are connected with said two sheets by means of round recesses, on which through holes are provided for air flow, so it lacks potential supporting force against shock or pressure.
23. U.S. Pat. No. 2,028,060 titled xe2x80x9cProtectorxe2x80x9d acquired by Gilbert is an inflatable sport protecting cushion made of a plurality of square hollow tubes combined together and communicating with each other by means of connecting tubes. As it is provided with two sheets having square grooves, the square tubes may be deformed after being inflated so that the surface may not be flat enough.
24. U.S. Pat. No. 4,670,995 titled xe2x80x9cMethod for Manufacturing Soles with an Air Cushionxe2x80x9d acquired by the same applicant as the present application is a shoe sole having a structure of two sheets provided with round recesses. Although it has an even pressure pervasion owing to the communication air-cells, flexibility and an inherent supporting force against pressure, it has a drawback that the smoothness of the surface is not so good after being inflated because of the pending supporting force of the air cells.
The U.S., French, German and Belgian patents discussed above have common drawbacks that they have little or no inherent supporting force against pressure or shock, little flexibility, and can have an unsmooth surface after being filled with air. Besides, they cannot be combined to make up an air cushion with a cubic structure to conform to a curved surface of the human body and to have an inherent shock-absorbing force, excellent flexibility and evenly pervasive pressure.
In view of the defects in conventional shock-absorbing cushions, this applicant has acquired U.S. Pat. Nos. 4,670,995 and 7,422,131, Japanese Patent No. 1,709,140, Korean Patent No. 35,963 and Australian Patent No. 564,808 for an invention relating to an air cushion for a shoe sole. Now this applicant has further devised the present invention to furnish a shock-absorbing cushion that has the possibility of adjusting the inner pressure, flexibility in being adaptable to any hollow shape, the largest shock-absorbing dimension, and an inherent supporting force against pressure or shock. That is, this shock-absorbing cushion has in its hollow interior, a plurality of air cells communicating with one another, so that when inflated, air can flow here and there in the interior, and an inherent shock-absorbing elasticity even if it is broken. It can widely be applied to sports goods such as leg or shin guards, knee pads, shoulder pads, racket grips, football helmets, shoe soles, tools, seat cushions, and packing material, utilizing the features just mentioned above.
The shock-absorbing cushion according to the present invention comprises two sheets sealed together at the periphery to have a hollow interior. One of the two sheets, the upper or the lower, is flat, smooth and completely closed, i.e., it is continuous and has no recesses or other depressions formed therein but the other sheet, the lower or the upper, is provided with a plurality of recesses which may be holes and/or grooves with vertical walls which may or may not link with said one of the sheets. If the vertical walls of the holes or the grooves do not link with said one of the sheets, they have their bottoms separated from said one of the sheets with gaps.
The holes and/or the grooves can be planned to be located all over the lower sheet, regularly or irregularly.
The vertical walls of the holes and/or the grooves pull both the sheets together, making up a cubic supporting structure of the shock-absorbing cushion, which has a hollow interior filled with air, a gas, a liquid or a semi-solid material. Then the cubic supporting structure can have an inherent supporting force against pressure or shock.
If the vertical walls of the holes and/or the grooves are linked to said one of the sheets, the shock-absorbing cushion can hardly swell up or deform after being inflated with air or filled in with a liquid or a semi-solid material. But if said walls are not linked with said one of the sheets, the shock-absorbing cushion may swell up a little after being inflated, as it has a freer hollow interior.
The lengthwise cross-section of each recess can be triangular, square, round etc., and the crosswise cross-section of the hole can be vertically or non-vertically trapezoidal, triangular, square, etc.
The groove can have its lengthwise cross-section as a straight or curved line and its crosswise cross-section as vertically or non-vertically trapezoidal, triangular, square, etc.
The grooves can also make the shock-absorbing cushion be provided with a plurality of independent air chambers and a tubal passage can be provided between the grooves to communicate the given air chambers so as to furnish said cushion with a degree of flexibility for bending.
An end slip can be respectively attached at both the lengthwise ends of the shock-absorbing cushion to glue, stick or sew together said cushions when applied to a racket grip, or the like.
The shock-absorbing cushion can additionally be provided with a hollow tube, which can be connected with an air valve, a one-way valve or a connecting tube of another air cushion system.
The shock-absorbing cushion in the present invention can be applied to sports goods such as a knee pad, a shoulder pad, a football helmet, a racket grip, a shoe sole, a shoe tongue, a shoe counter, and packing material, and so on. The holes and/or the grooves can be combined together with a wide variety of combinations to suit to the objects that the shock-absorbing cushion is applied to.